Immanuel Kant (2)

Like many of his contemporaries, Kant was greatly impressed with the scientific advances made by Newton and others. This new evidence of the power of human reason called into question for many the traditional authority of politics and religion. In particular, the modern mechanistic view of the world called into question the very possibility of morality; for, if there is no agency, there cannot be any responsibility.

The aim of Kant's critical project is to secure human autonomy, the basis of religion and morality, from this threat of mechanism - and to do so in a way that preserves the advances of modern science. In the Critique of Pure Reason, Kant summarizes his philosophical concerns in the following three questions:

- What can I know?
- What should I do?
- What may I hope?

The Critique of Pure Reason focuses upon the first question and opens a conceptual space for an answer to the second question. It argues that even though we cannot strictly know that we are free, we can - and for practical purposes, must - think of ourselves as free. In Kant's own words, "I had to deny knowledge in order to make room for faith." Our rational faith in morality is further developed in the Groundwork of the Metaphysics of Morals and the Critique of Practical Reason.

The Critique of the Power of Judgment argues we may rationally hope for the harmonious unity of the theoretical and practical domains treated in the first two Critiques on the basis, not only of its conceptual possibility, but also on the basis of our affective experience of natural beauty and, more generally, the organization of the natural world. In Religion within the Bounds of Mere Reason, Kant endeavors to complete his answer to this third question.

These works all place the active, rational human subject at the center of the cognitive and moral worlds. In brief, Kant argues that the mind itself necessarily makes a constitutive contribution to knowledge, that this contribution is transcendental rather than psychological, and that to act autonomously is to act according to rational moral principles.

Kant's Critical Project

Kant's 1781 (revised 1787) Critique of Pure Reason has often been cited as the most significant volume of metaphysics and epistemology in modern philosophy. In the first Critique, and later on in other works as well, Kant frames the "general" and "real problem of pure reason" in terms of the following question: "How are synthetic judgments a priori possible?" To understand this claim, it is necessary to define some terms. First, Kant makes a distinction between two sources of knowledge:

- Cognitions a priori: "cognition independent of all experience and even of all the impressions of the senses".
- Cognitions a posteriori: cognitions that have their sources in experiencethat is, which are empirical.

Second, he makes a distinction in terms of the form of knowledge:
- Analytic judgements: judgements in which the predicate concept is contained in the subject concept; e.g., "All bachelors are unmarried", or "All bodies take up space". These can also be called "judgments of clarification".

- Synthetic judgements: judgements in which the predicate concept is not contained in the subject concept; e.g., "All bachelors are alone", "All swans are white", or "All bodies have weight". These can also be called "judgments of amplification".

An analytic judgement is true by nature of strictly conceptual relations. All analytic judgements are a priori since basing an analytic judgement on experience would be absurd. By contrast, a synthetic judgement is one the content of which includes something new in the sense that it is includes something not already contained in the subject concept. The truth or falsehood of a synthetic statement depends upon something more than what is contained in its concepts. The most obvious form of synthetic judgement is a simple empirical observation.

Philosophers such as David Hume believed that these were the only possible kinds of human reason and investigation, which Hume called "relations of ideas" and "matters of fact". Establishing the synthetic a priori as a third mode of knowledge would allow Kant to push back against Hume's skepticism about such matters as causation and metaphysical knowledge more generally. This is because, unlike a posteriori cognition, a priori cognition has "true or strict... universality" and includes a claim of "necessity". Kant himself regards it as uncontroversial that we do have synthetic a priori knowledgeespecially in mathematics. That 7 + 5 = 12, he claims, is a result not contained in the concepts of seven, five, and the addition operation.

Yet, although he considers the possibility of such knowledge to be obvious, Kant nevertheless assumes the burden of providing a philosophical proof that we have a priori knowledge in mathematics, the natural sciences, and metaphysics. It is the twofold aim of the Critique both to prove and to explain the possibility of this knowledge. Kant says "There are two stems of human cognition, which may perhaps arise from a common but to us unknown root, namely sensibility and understanding, through the first of which objects are given to us, but through the second of which they are thought."

Kant's term for the object of sensibility is intuition, and his term for the object of the understanding is concept. In general terms, the former is a non-discursive representation of a particular object, and the latter is a discursive (or mediate) representation of a general type of object. The conditions of possible experience require both intuitions and concepts, that is, the affection of the receptive sensibility and the actively synthesizing power of the understanding. Thus the statement: "Thoughts without content are empty, intuitions without concepts are blind".

Kant's basic strategy in the first half of his book will be to argue that some intuitions and concepts are purethat is, are contributed entirely by the mind, independent of anything empirical. Knowledge generated on this basis, under certain conditions, can be synthetic a priori. This insight is known as Kant's "Copernican revolution", because, just as Copernicus advanced astronomy by way of a radical shift in perspective, so Kant here claims do the same for metaphysics.

The second half of the Critique is the explicitly critical part. In this "transcendental dialectic", Kant argues that many of the claims of traditional rationalist metaphysics violate the criteria he claims to establish in the first, "constructive" part of his book. As Kant observes, however, "human reason, without being moved by the mere vanity of knowing it all, inexorably pushes on, driven by its own need to such questions that cannot be answered by any experiential use of reason". It is the project of "the critique of pure reason" to establish the limits as to just how far reason may legitimately so proceed.

Doctrine of Transcendental Idealism

The section of the Critique entitled "The transcendental aesthetic" introduces Kant's famous metaphysics of transcendental idealism. Something is "transcendental" if it is a necessary condition for the possibility of experience, and "idealism" denotes some form of mind-dependence that must be further specified. The correct interpretation of Kant's own specification remains controversial.

The metaphysical thesis then states that human beings only experience and know phenomenal appearances, not independent things-in-themselves, because space and time are nothing but the subjective forms of intuition that we ourselves contribute to experience. Nevertheless, although Kant says that space and time are "transcendentally ideal" - the pure forms of human sensibility, rather than part of nature or reality as it exists in-itself - he also claims that they are "empirically real", by which he means "that 'everything that can come before us externally as an object' is in both space and time, and that our internal intuitions of ourselves are in time". However Kant's doctrine is interpreted, he wished to distinguish his position from the subjective idealism of Berkeley.

Paul Guyer, although critical of many of Kant's arguments in this section, writes of the "Transcendental Aesthetic" that it "not only lays the first stone in Kant's constructive theory of knowledge; it also lays the foundation for both his critique and his reconstruction of traditional metaphysics. It argues that all genuine knowledge requires a sensory component, and thus that metaphysical claims that transcend the possibility of sensory confirmation can never amount to knowledge."

Interpretive Disagreements

One interpretation, known as the "two-world" interpretation, regards Kant's position as a statement of epistemological limitation, meaning that we are not able to transcend the bounds of our own mind, and therefore cannot access the "thing-in-itself". On this particular view, the thing-in-itself is not numerically identical to the phenomenal empirical object. Kant also spoke, however, of the thing-in-itself or transcendent object as a product of the (human) understanding as it attempts to conceive of objects in abstraction from the conditions of sensibility.

Following this line of thought, a different interpretation argues that the thing-in-itself does not represent a separate ontological domain but simply a way of considering objects by means of the understanding alone; this is known as the "two-aspect" view. On this alternative view, the same objects to which we attribute empirical properties like color, size, and shape are also, when considered as they are in themselves, the things-in-themselves, otherwise inaccessible to human knowledge.

Kant's Theory of Judgment

Following the "Transcendental Analytic" is the "Transcendental Logic". Whereas the former was concerned with the contributions of the sensibility, the latter is concerned, first, with the contributions of the understanding ("Transcendental Analytic") and, second, with the faculty of reason as the source of both metaphysical errors and genuine regulatory principles ("Transcendental Dialectic"). The "Transcendental Analytic" is further divided into two sections.

The first, "Analytic of Concepts", is concerned with establishing the universality and necessity of the pure concepts of the understanding (i.e., the categories). This section contains Kant's famous "transcendental deduction". The second, "Analytic of Principles", is concerned with the application of those pure concepts in empirical judgments. This second section is longer than the first and is further divided into many sub-sections.

Transcendental Deduction of the Categories of the Understanding

The "Analytic of Concepts" argues for the universal and necessary validity of the pure concepts of the understanding, or the categories, for instance, the concepts of substance and causation. These twelve basic categories define what it is to be a thing in generalthat is, they articulate the necessary conditions according to which something is a possible object of experience. These, in conjunction with the a priori forms of intuition, are the basis of all synthetic a priori cognition.

According to Guyer and Wood, "Kant's idea is that just as there are certain essential features of all judgments, so there must be certain corresponding ways in which we form the concepts of objects so that judgments may be about objects."

Kant provides two central lines of argumentation in support of his claims about the categories. The first, known as the "metaphysical deduction", proceeds analytically from a table of the Aristotelian logical functions of judgment. As Kant was aware, this assumes precisely what the skeptic rejects, namely, the existence of synthetic a priori cognition. For this reason, Kant also supplies a synthetic argument that does not depend upon the assumption in dispute.

This argument, provided under the heading "Transcendental Deduction of the Pure Concepts of the Understanding", is widely considered to be both the most important and the most difficult of Kant's arguments in the Critique. Kant himself said that it is the one that cost him the most labor. Frustrated by its confused reception in the first edition of his book, he rewrote it entirely for the second edition.

The "Transcendental Deduction" gives Kant's argument that these pure concepts apply universally and necessarily to the objects that are given in experience. According to Guyer and Wood, "He centers his argument on the premise that our experience can be ascribed to a single identical subject, via what he calls the 'transcendental unity of apperception,' only if the elements of experience given in intuition are synthetically combined so as to present us with objects that are thought through the categories."

Kant's principle of apperception is that "The I think must be able to accompany all my representations; for otherwise something would be represented in me that could not be thought at all, which is as much as to say that the representation would either be impossible or else at least would be nothing for me." The necessary possibility of the self-ascription of the representations of self-consciousness, identical to itself through time, is an a priori conceptual truth that cannot be based on experience. This is only a bare sketch of one of the arguments that Kant presents.

Principles of Pure Understanding

Kant's deduction of the categories in the "Analytic of Concepts", if successful, demonstrates its claims about the categories only in an abstract way. The task of the "Analytic of Principles" is to show both that they must universally apply to objects given in actual experience (i.e., manifolds of intuition) and how it is they do so. In the first book of this section on the "schematism", Kant connects each of the purely logical categories of the understanding to the temporality of intuition to show that, although non-empirical, they do have purchase upon the objects of experience.

The second book continues this line of argument in four chapters, each associated with one of the category groupings. In some cases, it adds a connection to the spatial dimension of intuition to the categories it analyzes. The fourth chapter of this section, "The Analogies of Experience", marks a shift from "mathematical" to "dynamical" principles, that is, to those that deal with relations among objects. Some commentators consider this the most significant section of the Critique. The analogies are three in number:

- Principle of persistence of substance: Kant is here concerned with the general conditions of determining time-relations among the objects of experience. He argues that the unity of time implies that "all change must consist in the alteration of states in an underlying substance, whose existence and quantity must be unchangeable or conserved."

- Principle of temporal succession according to the law of causality: Here Kant argues that "we can make determinate judgments about the objective succession of events, as contrasted to merely subjective successions of representations, only if every objective alteration follows a necessary rule of succession, or a causal law." This is Kant's most direct rejoinder to Hume's skepticism about causality.

- Principle of simultaneity according to the law of reciprocity or community: The final analogy argues that "determinate judgments that objects (or states of substance) in different regions of space exists simultaneously are possible only if such objects stand in mutual causal relation of community or reciprocal interaction." This is Kant's rejoinder to Leibniz's thesis in the Monadology.

The fourth section of this chapter, which is not an analogy, deals with the empirical use of the modal categories. That was the end of the chapter in the A edition of the Critique. The B edition includes one more short section, "The Refutation of Idealism". In this section, by analysis of the concept of self-consciousness, Kant argues that his transcendental idealism is a "critical" or "formal" idealism that does not deny the existence of reality apart from our subjective representations.

The final chapter of "The Analytic of Principles" distinguishes phenomena, of which we can have genuine knowledge, from noumena, a term which refers to objects of pure thought that we cannot know, but to which we may still refer "in a negative sense".

An Appendix to the section further develops Kant's criticism of Leibnizian-Wolffian rationalism by arguing that its "dogmatic" metaphysics confuses the "mere features of concepts through which we think things... [with] features of the objects themselves". Against this, Kant reasserts his own insistence upon the necessity of a sensible component in all genuine knowledge.

Critique of Metaphysics

The second of the two Divisions of "The Transcendental Logic", "The Transcendental Dialectic", contains the "negative" portion of Kant's Critique, which builds upon the "positive" arguments of the preceding "Transcendental Analytic" to expose the limits of metaphysical speculation. In particular, it is concerned to demonstrate as spurious the efforts of reason to arrive at knowledge independent of sensibility. This endeavor, Kant argues, is doomed to failure, which he claims to demonstrate by showing that reason, unbounded by sense, is always capable of generating opposing or otherwise incompatible conclusions.

Like "the light dove, in free flight cutting through the air, the resistance of which it feels", reason "could get the idea that it could do even better in airless space". Against this, Kant claims that, absent epistemic friction, there can be no knowledge. Nevertheless, Kant's critique is not entirely destructive. He presents the speculative excesses of traditional metaphysics as inherent in our very capacity of reason. Moreover, he argues that its products are not without some (carefully qualified) regulative value.

On the Concepts of Pure Reason

Kant calls the basic concepts of metaphysics "ideas". They are different from the concepts of understanding in that they are not limited by the critical stricture limiting knowledge to the conditions of possible experience and its objects. "Transcendental illusion" is Kant's term for the tendency of reason to produce such ideas. Although reason has a "logical use" of simply drawing inferences from principles, in "The Transcendental Dialectic", Kant is concerned with its purportedly "real use" to arrive at conclusions by way of unchecked regressive syllogistic ratiocination.

The three categories of relation, pursued without regard to the limits of possible experience, yield the three central ideas of traditional metaphysics:
- The soul: the concept of substance as the ultimate subject;
- The world in its entirety: the concept of causation as a completed series; and
- God: the concept of community as the common ground of all possibilities.

Although Kant denies that these ideas can be objects of genuine cognition, he argues that they are the result of reason's inherent drive to unify cognition into a systematic whole. Leibnizian-Wolffian metaphysics was divided into four parts: ontology, psychology, cosmology, and theology. Kant replaces the first with the positive results of the first part of the Critique. He proposes to replace the following three with his later doctrines of anthropology, the metaphysical foundations of natural science, and the critical postulation of human freedom and morality.